The invention relates generally to communication across components in a beacon enabled wireless personal area network. More particularly, the invention relates to a technique for synchronizing the local clocks of personal area network nodes.
A wireless personal area network allows wireless communication among local devices of the network, generally employing lower data rates and operating at lower power. In a beacon enabled wireless personal area network, such as a network adhering to IEEE standard 802.15.4, a network controller may send messages known as beacons to all devices of the network to specify when local devices may send and receive messages.
In the beacon enabled wireless personal area network, communication among the local devices and communication between the local devices and the network controller may take place during a series of device communication slots collectively known as a superframe. A superframe is bounded by beacons, e.g., a first beacon may indicate the start of a superframe and a second beacon may indicate the end. Devices may be scheduled to communicate during one or more of the superframe slots. Because the personal area network may utilize a low data rate, the availability of the superframe slots may be limited, particularly as the number of local devices on the personal area network increases. Moreover, local devices in a power save mode may periodically exit the power save mode to listen for beacons, which consumes power. The local devices in the power save mode may also periodically exit the power save mode to listen for time synchronization messages in one or more of the superframe slots, consuming additional power.